JPS5917434B2 - electronic musical instruments - Google Patents

Description

[Detailed Description of the Invention] This invention generates a fundamental wave (fundamental tone) and its harmonic components (overtones) corresponding to the pitch of an operating key, and generates the fundamental wave and harmonic components by corresponding amplitude coefficients. This is a harmonic synthesis method that forms musical tones by weighting and adding them together.

The present invention relates to improvements in electronic musical instruments, and particularly to electronic musical instruments that can produce natural and rich musical tones by temporally varying the amplitude coefficient. A. Description of the Prior Art Some harmonic synthesis electronic musical instruments obtain musical tones by sequentially calculating amplitude values at successive sample points of a musical sound waveform 5 based on equation (1). .

1027c X0(qR)=ΣCnSin−nqR・・・・・・・・・
・(1) n ■ 1W (q=1, 2, ・ ・ ・ ・ ・
・ ・ ) Here, 15Xo (qR)・・・・・・・・・
- Waveform amplitude value at each sample point of the musical waveform.

R: A numerical value proportional to the frequency (pitch) of a generated musical tone (hereinafter referred to as a frequency number).

n ・・・・・・Represents the order of harmonic components including the fundamental wave, where 0n■1 is the fundamental wave (fundamental tone), n=2 is the second
Harmonic (2nd harmonic), n=3 is 3rd harmonic (3rd harmonic)
Corresponds to...

Cn......Amplitude coefficient (Fourier coefficient) for harmonic components of each order.

5N・・・・・・Number of sample points of musical sound waveform.

W: Number of harmonics included in amplitude calculation at each sample point. There is a relationship of W=N/2. What is an example of an electronic musical instrument using this harmonic synthesis method? 0
It is constructed as shown in FIG.

In the figure, 1 is a key switch circuit provided in the keyboard section, which has key switches corresponding to each key on the keyboard section, and when a certain key is pressed, the corresponding key switch operates. , is configured to output 15 signals of logical value "1" to its output line.This key switch circuit 1 has a built-in single tone priority circuit, and if two or more key switches operate at the same time, , the Sl2 signal is output only to the output line corresponding to the key switch with a high priority.The output line corresponding to each key switch of the key switch circuit 1 has a frequency number R corresponding to the pitch of each key. It is connected to the input side of the stored frequency number memory 2, and when a certain key is pressed, it is addressed by the output of the key switch circuit 1 and the frequency corresponding to the pitch of that key is sent from the frequency number memory 2. The number R is read out. On the other hand, the clock oscillator 3 outputs a clock pulse Tc of a constant period, and this clock pulse Tc is divided by w by the counter 4 and is used as a calculation interval timing signal T.
It becomes x.

In this case, "W" is the total number of harmonics to be synthesized, for example, the total number of harmonics to be synthesized,
For example, when combining up to the 16th harmonic, "W=16". The calculation interval timing signal generated in this manner is supplied to the gate 5. This gate 5 opens the gate every time the calculation interval timing signal is supplied, and supplies the frequency number R output from the frequency number memory 2 to the pitch interval adder 6. The pitch section adder 6 is connected to the gate 5.
Every time the frequency number R is supplied via the (that is, every time the calculation interval timing signal Tx is generated), the frequency number R is accumulated and increases as 1R12R, 3R, etc. Outputs the value QR. When the accumulated value QR exceeds the modulus N of the adder 6, it overflows and becomes all zero, and thereafter, the same accumulation operation is performed again every time the calculation interval timing signal Tx is generated.

Thus, the accumulated value QR, which changes with each occurrence of the calculation interval timing signal Tx, is supplied to the harmonic interval adder 8 via the gate 7 which is gated by the clock pulse Tc. In this case, since the clock pulse Tc has a frequency w times the calculation interval timing signal TXf), the gate 7 is opened w times during one cycle of the calculation interval timing signal Tx. As a result, the harmonic section adder 8 sequentially adds the cumulative value QR output from the gate 7 every time the clock pulse Tc occurs, and outputs the cumulative value NqR. When the w times of accumulation are completed, it is set by the calculation interval timing signal Tx, and the same operation is performed thereafter. Therefore, this harmonic interval adder 8 outputs the clock pulse Tc during one period of the calculation interval timing signal Tx.
The accumulated value NqR (n=1, 2,
3......) is occurring. This accumulated value NqR is decoded in the memory address decoder 9, and the decoded output is sent as an address signal to the sine function memory 10, which stores the amplitude value of each sample point of one period of the sine wave waveform in each address. The sine amplitude value 7L sinτWnqR is read out from the memory 10.

As is clear from the above explanation, the cumulative value QR of the pitch interval adder 6 indicates the sample point at which the musical waveform amplitude is to be calculated, and the cumulative value NqR of the harmonic interval adder 8 indicates the sample point at which the musical waveform amplitude is to be calculated. It represents the phase of the n-th harmonic at the sample point QR.

As a result, from the sine function memory 10, the sample point QR
The sine amplitude value Sin of each harmonic (including the fundamental wave) in
-NqR (n=1, 2°, . . . . W) is sequentially generated in the order of fundamental wave, 1X1 first harmonic, . . . .

In this case, the sample points to be calculated shift sequentially every time the calculation interval timing signal Tx is generated, but which sample point to shift to next is determined by the frequency number R. The frequency number R is proportional to the pitch of the operating key. Therefore, the sine amplitude IL width value (Sin-NqR) of the fundamental wave and its harmonics corresponding to the pitch of the operating key are sequentially generated from the sine function memory 10 in a time-sharing manner τTr.

On the other hand, the memory address control device 11 is modulo W.
The clock pulse Tc is sequentially counted in synchronization with the counter 4, and the count value is outputted to the harmonic coefficient memory 12 as an address signal.

The harmonic coefficient memory 12 stores a harmonic amplitude coefficient C corresponding to the optimum amplitude value of each harmonic in order to obtain a desired musical timbre.
n is stored in each address, and when an address signal that counts up in synchronization with the clock pulse Tc is supplied from the memory address control device 11, the amplitude of the fundamental wave and its harmonics stored in each address is calculated. The harmonic amplitude coefficients Cn to be set are sequentially read out. This harmonic amplitude coefficient Cn is multiplied by an envelope signal EB, which will be described later, in a coefficient scaler 13 at a temperature of 0.degree. C., and then outputted to a harmonic amplitude multiplier 14 as a harmonic amplitude coefficient Cg. The harmonic amplitude multiplier 14 calculates the sine amplitude value π Sin-J of the fundamental wave and its harmonics read out in a time-division manner for each sample point from the sine function memory 10 and the harmonics set for each harmonic. After multiplying the wave amplitude coefficient Cgo and weighting each amplitude by the amplitude coefficient, the multiplication value Fn-Cn'Sin-NqR
W is supplied to the accumulator 15.

In this case, since the harmonic section adder 8 and the memory address control device 11 are synchronized with each other, the harmonic amplitude coefficient Cn' sequentially read out for each harmonic is the corresponding harmonic sine amplitude value Sin-NqR. This sets the amplitude value Fn for each harmonic 1XI wave.

The accumulator 15 sequentially accumulates the amplitude value Fn of each harmonic output from the harmonic amplitude multiplier 14. When the calculation interval timing signal Tx is generated, the gate 16 opens and the accumulated value of the accumulator 15 (representing the amplitude value at a certain sample point of the musical waveform) is output to the D-A converter 17. At the same time, the accumulator 15 is reset and the same accumulation operation as described above is performed again in order to calculate the amplitude value at the next musical waveform sample point. Therefore, the D-A converter 17 receives the cumulative value of the set amplitude values of the fundamental wave and its harmonics at each sample point of the musical sound waveform corresponding to the pitch of the pressed key as the calculation interval timing signal. This accumulated value is converted into an analog signal and supplied to the sound system 18, so that each signal with a pitch corresponding to the pressed key and stored in the harmonic coefficient memory 12 is supplied every time Tx occurs. A musical tone having a tone corresponding to a harmonic amplitude coefficient Cn that sets a harmonic amplitude ratio is generated. On the other hand, an amplitude envelope is assigned to a generated musical tone in the following manner.

A switch opening/closing detector 19 detects that a key switch in the key switch circuit 1 is closed, generates an attack mode signal AM, and supplies this attack mode signal AM to an attack/decay cycle counter 20 and a memory select device 21. The attack/decay cycle counter 20 has an attack time and a decay time set as a function of the frequency of the generated musical tone, and counts the overflow signal 0F of the pitch section adder 6 to set the attack time and decay time. In other words, the attack/decay cycle counter 20 receives the attack signal AM
When is input, the attack cycle counter is selected and sequentially counts the overflow signal 0F (corresponding to the period of the generated musical tone) of the pitch section adder 6, and selects the count value that increases in accordance with the frequency of the generated musical tone in the memory. Supplied to the device 21. The memory select device 21 selects the attack scale factor memory 22 by supplying the attack mode signal AM, and uses the count value output from the attack decay cycle counter 20 in the selected attack scale factor memory 22. as an address signal. Each address of the attack scale factor memory 22 stores each sample point amplitude value corresponding to a desired attack waveform, and by addressing with the count output of the attack decay cycle counter 20, the attack part can be adjusted. Envelope signal EB is read out. When the counter value of the attack cycle counter 20 reaches the set value, the counting operation is stopped and this state becomes a sustain state. Next, when the switch opening/closing detector 19 detects the opening operation of the key switch accompanying the release of the key, it generates a decay mode signal DM. When the decay mode signal DM is generated, the decay holding control circuit 23 controls the frequency number memory 2 to hold and continue outputting the previously outputted frequency number R. Therefore, musical tones continue to be generated even if the temperature is lowered to 0.degree. C. after the key is released. Further, with the generation of the decay mode signal DM, the attack decay cycle counter 20 selects the decay cycle counter, and the memory select device 21 selects the decay scale factor memory 24. When the overflow signal 0F is generated from the interval adder 6 in this state, the decay cycle counter 20 sequentially counts up, and the count value is used to count up the decay cycle counter 20 in which the amplitude value of each sample point of the decay waveform is stored. The scale factor memory 24 is read to generate the decay envelope signal EB. The attack and decay envelope signals EB generated in this way are multiplied by the harmonic amplitude coefficient Cn read out from the harmonic coefficient memo 1 and 2 in the coefficient scaler 13 to apply attack and decay to the generated musical tone. is given an amplitude envelope of
When the decay cycle counter 20 counts the overflow signal 0F of the pitch section adder 6 to a set value, the decay cycle counter 20 controls the decay holding control circuit 23 to release the holding operation, thereby ending the decay operation. With this configuration, each component of the fundamental wave and its harmonics corresponding to the pitch of the operating key is generated, and each of these components is multiplied by an amplitude coefficient and synthesized, thereby achieving a harmonic synthesis method. A musical tone is generated.

Incidentally, an electronic musical instrument with such a configuration was disclosed in Japanese Patent Application Laid-open No. 1973-
Since it is disclosed in Japanese Patent No. 90217, a detailed explanation of the configuration and operation of each part will be omitted. B. Disadvantages of the Prior Art As is clear from the above explanation, the conventional electronic musical instrument using the harmonic synthesis method described above has a harmonic coefficient memory that maintains a frequency corresponding to the pitch of the pressed key from the time the musical tone is generated to the end. A musical tone is generated by adding a volume envelope to a musical waveform of a tone set by the harmonic amplitude coefficient Cn stored in the harmonic amplitude coefficient Cn.

Therefore, the amplitude of this musical tone only changes due to envelope control, and the waveform shape is the same repeatedly from the time the musical tone is generated to the end, and as a result,
The timbre of the generated musical tone is always the same and does not change. However, in general, the sound produced by a natural musical instrument changes slightly in its timbre (waveform shape) from the beginning to the end, and this creates a rich, natural sound. It's becoming a sound. Therefore, the above-mentioned conventional harmonic synthesis electronic musical instruments have the disadvantage that the generated musical sounds do not have the richness of natural musical instruments, resulting in extremely monotonous performance sounds.

C. Purpose of the Invention In view of the above-mentioned drawbacks of the conventional harmonic synthesis type electronic musical instrument, the present invention provides a harmonic wave generator which controls the amplitude of each component of the fundamental wave and its harmonic waves read from a sine function memory using a simple configuration. By varying the amplitude coefficients Cn over time, the timbre of the generated musical tone can be changed from the time the musical tone is generated until the end of the musical tone, so that a natural and rich musical tone can be obtained. Our goal is to provide electronic musical instruments that are designed to meet your needs.

Hereinafter, the electronic musical instrument according to the present invention will be explained in detail using the drawings. The same symbols are used for the same parts as in Figure 1 (・
There is.

In the figure, 25 is a one-shot circuit that inputs the switch close detection signal of the switch open/close detector 19 and outputs a pulse synchronized with the rising edge of the signal, and 26 is a frequency that oscillates a low frequency clock signal LFC of, for example, 100 Hz or less. A variable low frequency oscillator, 27 is a counter that is set by the pulse output from the one shot circuit 25 and counts the low frequency clock signal LFC from the low frequency oscillator 26, 28 inverts the most significant bit signal of the counter 27. An inverter 29 determines the coincidence between the low frequency clock signal LFC from the low frequency oscillator 26 and the output signal of the inverter 28, and supplies the output to the counter 27 as a count signal; 31 is an AND gate that is determined for each order. a memory in which the function value f(n) of each order is sequentially read out in a time-sharing manner according to the address signal n output from the memory address control device 11;
2 is a multiplier that modulates the address signal t for each order by multiplying the address signal t output from the counter 27 and the function value f(n), and outputs the modulated address signal t as an address signal tf(n); 33 stores multiple types of amplitude coefficients (・
This is a harmonic coefficient memory from which a harmonic amplitude coefficient Cnt7, which changes over time differently for each order, is read out according to the modulated address signal tf(n). Here, the low frequency oscillator 26, the counter 27, the inverter 28, and the AND gate 29 constitute address signal generating means for generating an address signal t that changes as time elapses after the key is pressed. The signal f(
n) constitutes a control means that changes and controls the address signal t for each order, and the harmonic coefficient memory 33 constitutes an amplitude coefficient storage means that stores a plurality of types of amplitude coefficients.

In the electronic musical instrument configured as described above, when a key on the keyboard section is pressed at 0.degree. C., the corresponding key switch closes and a "1" signal is output to the corresponding output line of the key switch circuit 1.

In this case, since the key switch circuit 1 has a built-in single-tone priority circuit, even if multiple keys are pressed, the 1" signal is output only to the one output line with the highest priority. The output signal is outputted by addressing the frequency number memory 2 and reading out the frequency number R corresponding to the pitch of the pressed key.
is supplied to a pitch interval adder 6 via a gate 5 which is opened in response to a calculation interval timing signal Tx created by dividing the frequency by w in a counter 4.

The pitch interval adder 6 sequentially adds the frequency numbers R supplied each time the calculation interval timing signal Tx is generated to obtain an accumulated value QR.
Output. This accumulated value QR is supplied to a harmonic section adder 8 via a gate 7 which is opened by the clock pulse Tc, and this harmonic section adder 8 converts the accumulated value QR into one part of the calculation section timing signal Tx. 1, R, 2, R, 3qR... at the timing of clock pulse Tc within the cycle.
. . . are sequentially added to generate an accumulated value NqR that specifies the phase of the sine amplitude value at the sample point of each harmonic (including the fundamental wave). After this accumulated value NqR is decoded in the memory address decoder 9,
Address the sine function memo l river 0 and calculate the sine wave 1 of each harmonic.
! The width value Sin Demand NqR is read out in a time-division manner.

This operation is performed on sequential sample points of the musical sound waveform corresponding to the pressed key pitch every time a calculation interval timing signal signature occurs. On the other hand, memory address control device 11
is the next harmonic corresponding to the sine amplitude value Sin-NqR read from the sine function memory 10 by counting the clock pulse Tc in synchronization with the counter 4 and outputting the count value as the address signal n. Specify 1λ1 number.

Further, the switch opening/closing detector 19 detects the closing operation of the key switch accompanying the depression of the key. The one-shot circuit 25 is triggered by the rising edge of the detection signal output from the switch opening/closing detector 19 and operates, outputting a narrow pulse to reset the counter 27. As a result,
The counter 27 becomes all zeros, and the output of the inverter 28 which inverts the most significant bit signal becomes "1". The counter 27 receives the low frequency clock signal LFC.
are counted sequentially. The count value of the counter 27 is output as an address signal t, and this address signal t increases as t1, T2, T3, etc. at a slow cycle corresponding to the cycle of the low frequency clock signal LFC. do.
Then, the product of the function f(n) read out from the memory 31 by the address signal n specifying the harmonic order from the memory address control device 11 and the address signal t output from the counter 27 is calculated by the multiplier 32. An address signal tf(n) calculated by , and modulated for each order by a function f(n) is output, and the harmonic coefficient memory 33 is addressed by this address signal. address signal t-
Since f(n) changes in an extremely complicated manner with the passage of time, the harmonic amplitude coefficient Cnt' read out from the harmonic coefficient memory 33 changes in a complicated manner, and the timbre of the generated musical tone changes with the passage of time. In this way, each harmonic amplitude coefficient Cnt', which changes over time depending on the harmonic order, is output from the sine function memory 10 in the harmonic amplitude multiplier 14.
When multiplied by the sine amplitude value Sin:-NqR of each harmonic, the amplitude π value Fn of each harmonic increases over time.
(Cntsin-NqR) will change in different ways, and as a result, the accumulated value of the accumulator 15 that accumulates the amplitude value Fn of each harmonic for each sample point will change. It changes with the passage of time from the key time.

Therefore, the sound system 18 that converts the output of the D-A converter 17 into musical tones generates musical tones whose timbre changes over time, similar to the pronunciation of natural musical instruments, producing rich, natural sounds. The result is a musical tone. In addition, counter 2
7, when the most significant bit becomes S1'', the output of the inverter 28 becomes ``0'', the AND gate 29 is closed, and the counting operation is stopped.Therefore, during the period in which the timbre change of the generated musical tone is obtained, the output of the inverter 28 becomes ``0''. This timbre change period, which is the period from the start until the most significant bit of the counter 27 becomes 12, can be easily adjusted by variably setting the oscillation cycle of the low frequency oscillator 26. Note that the amplitude envelope is assigned to the musical tone by the switch opening/closing detector 1.
It is assumed that the sound system 18 is provided with an envelope controller that operates with the output of the envelope controller 9, and that the musical tone signal is multiplied by the envelope control signal output from the envelope controller.

In addition, the counter 4, pitch section adder 6, harmonic section adder 8, and memory address control device 11 are controlled by a signal generated at the start of key depression, for example, a rising differential signal of a signal output from the switch opening/closing detection device 19. By setting the temperature, the synchronization relationship at the start of operation is maintained. In an electronic musical instrument configured in this way, the timbre can be easily changed by simply changing the function f(n) stored in the relatively small memory 31, and each order can be changed with one memory. can be shared, and there is no need to provide a memory for each order, simplifying the configuration.

E. Effects of the Invention As explained above, the electronic musical instrument of the invention generates a fundamental wave and its harmonic components corresponding to the pitch of an operating key, and generates an address that changes with the passage of time after the key is pressed. The signal is changed and controlled for each order by a signal generated in a time-division manner corresponding to the order of each component, and the amplitude coefficients are sequentially read out from the amplitude coefficient storage means, and the amplitude of each component is weighted by this amplitude coefficient. As a result, the amplitude coefficient changes in a complex manner, and the timbre of the generated musical sound changes subtly over time, resulting in a sound state that is very close to that of a natural instrument, producing a natural and rich sound. It has an excellent effect of creating a musical tone.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional electronic musical instrument using a harmonic synthesis method, and FIG. 2 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention. 1...Key switch circuit, 2...Frequency number memory, 3...Clock oscillator, 4,
27... Counter, 5, 7, 16...
Gate, 6... Pitch section adder, 8...
・Harmonic interval adder, 9...Memory address decoder, 10...Sine function memory, 11.
...Memory address control device, 14...
Harmonic amplitude multiplier, 15... Accumulator, 17...
...DA converter, 18...Sound system, 19゜゜゜...Switch open/close detector, 25...
...Wanshiyot circuit, 26...Low frequency oscillator, 31... Memory, 32... Multiplier, 33... Harmonic coefficient memory.

Claims (1)

[Claims] 1 A harmonic generator that forms a musical tone by generating components corresponding to the fundamental wave and its harmonics that make up a musical tone, weighting the amplitude of each component by its corresponding amplitude coefficient, and then adding them together. A wave synthesis type electronic musical instrument includes an amplitude coefficient storage means that stores a plurality of types of amplitude coefficients, an address signal generation means that generates an address signal that changes as time elapses after a key is pressed, and an order of each of the above components. Correspondingly, control means for changing and controlling the address signal for each order by signals generated in a time-division manner is provided, and the amplitude coefficients are sequentially read out from the amplitude coefficient storage means according to the changed address signals, and An electronic musical instrument characterized in that the amplitudes of the corresponding components are weighted by amplitude coefficients.